A (poly)alkylene glycol chain-containing polymer has been used for various applications as a polymer having hydrophilicity and is particularly useful as a dispersant or the like. For example, it has a capability of reducing water for cement compositions such as cement paste, mortar and concrete, and the like and has been used widely as an admixture for cement, a concrete admixture, or the like and it is thus indispensable for composing civil engineering and construction structural objects and the like from the cement compositions. Such an admixture for cement is provided with a function of improving strength and durability of hardened products by improving the fluidity of the cement compositions and reducing water of the cement compositions. Among such water-reducing agents, because of a high water-reducing capability as compared with conventional naphthalene water-reducing agents and the like, a polycarboxylic acid admixture for cement or concrete admixture containing a polycarboxylic acid polymer has been practically used as a high performance AE water-reducing agent in many cases.
As such a polycarboxylic acid polymer preferable for an admixture for cement, copolymers of alkenyl ether alkylene oxide adducts and unsaturated carboxylic acids have been investigated. Specifically disclosed are binary copolymers of a poly(ethylene/propylene) glycol alkenyl ether and an unsaturated carboxylic acid as indispensable constituent units (e.g. refer to Japanese Kokai Publication Nos. Hei-10-194808 and Hei-11-106247), quaternary copolymers of (1) a polyethylene glycol (meth) allyl ether, (2) a polyalkylene glycol (meth) allyl ether, (3) (meth)acrylic acid, and (4) a sulfonic acid group-containing monomer (e.g. refer to Japanese Kokai Publication No. 2000-034151), and tertiary copolymers of (1) a polyethylene glycol (meth) allyl ether, (2) a polypropylene glycol (meth) allyl ether, and (3) an unsaturated carboxylic acid (e.g. refer to Japanese Kokai Publication No. 2001-220194).
Further disclosed examples are copolymers of an alkylene oxide (AO) adduct of an alkenyl ether having 2 to 4 carbon atoms and methacrylic acid (e.g. refer to Japanese Kokai Publication No. 2002-348161), copolymers of a methallyl ether AO adduct and acrylic acid (e.g. refer to Japanese Kokai Publication No. 2002-121055), tertiary copolymers of (1) an alkenyl AO adduct having 2 to 4 carbon atoms (addition mole number n=1 to 100), (2) an alkenyl ether AO adduct having 2 to 4 carbon atoms (addition mole number n=11 to 300), and (3) an unsaturated monocarboxylic acid, blends of copolymers of (1) and (3) with copolymers of (2) and (3) (e.g. refer to Japanese Kokai Publication No. 2003-221266), and admixture for cement, containing four components, that is, a copolymer (A) of an alkenyl ether AO adduct having 2 to 4 carbon atoms and maleic acid, an unsaturated polyalkylene glycol ether monomer, an alkenyl-free non-polymerizable polyalkylene glycol, and a polymer different from the copolymer (A) (e.g. refer to Japanese Kokai Publication No. 2006-522734).
However, in the case of use for cement compositions or the like, polymers are required to be excellent in various properties, inexpensive and have general versatility. There is still a margin to devise for improving the work efficiency in construction work fields such as civil engineering and construction structural objects and the like, or heightening the properties of concrete or the like by improving the dispersibility and water-reducing capability and improving the retention of fluidity of concrete or the like in production work fields to make the conditions of concrete or the like easier to work on.